The Twin Mountain occurrence is located at an elevation of approximately 1500 metres on a south-southwest-facing slope of Twin Mountain, approximately 5.5 kilometres north of the mouth of Sinmax Creek on Adams Lake.

The area is underlain by Devonian or older rocks of the Eagle Bay Formation consisting of calcareous chlorite-sericite- quartz schist within unit EBG (Map 56). The schists were derived largely from mafic to intermediate volcanic and volcaniclastic rocks. The metavolcanics contain several thin layers of limestone and dolomite, as well as remnant pillow basalt structures. The Tshinakin limestone member lies to the northeast of the property.

Mineralization occurs within a conformable northeast dipping zone of grey pyritic and calcareous chlorite-sericite-quartz schists enclosed within darker green chlorite schists of unit EBG (Map 56). The zone is several metres to over 10 metres wide and has been traced intermittently over a strike length of over 4 kilometres (Assessment Report 8942).

Galena-sphalerite-pyrite-chalcopyrite mineralization occurs within carbonate-quartz-barite lenses concordant to the schistosity. The carbonate is mainly dolomite with lesser calcite and siderite. The lenses range up to several metres thick and contain disseminations to massive pods, up to 30 centimetres wide, of galena and sphalerite.

A second parallel zone of mineralization is reported approximately 200 metres west of the main zone and comprises quartz-barite-dolomite veins with chalcopyrite(?) and galena(?) mineralization in a pyritic quartz-sericite schist that is up to 30 metres wide.

In 1936, six samples from trenches are reported to have yielded of up to 17.14 grams per tonne gold, 171.4 grams per tonne silver, 36.5 per cent lead and 3.7 per cent zinc (Annual Report 1936-D39).

In 1969, four select samples (35489, 35491, 35493 and 44938) from surface and underground workings are reported to have yielded from 0.04 to 0.23 per cent copper, 4.64 to 10.05 per cent lead, 1.54 to 7.10 per cent zinc, 18.5 to 54.9 grams per tonne silver and 0.34 to 1.02 grams per tonne gold (Assessment Report 2093).

In 1980, select grab samples from the second parallel zone of mineralization were estimated at 2 per cent copper, 1 per cent lead, 1 per cent zinc and 10 per cent barite (Assessment Report 8942).

In 1981, a subjective average value of 11 representative samples, taken from different locations along the mineralized zone, was reported at 0.18 per cent copper, 0.90 per cent lead, 2.15 per cent zinc, 8.9 grams per tonne silver and 0.17 gram per tonne gold, whereas the average of ‘higher-grade shoots’ was reported at 0.19 per cent copper, 3.4 per cent lead, 3.9 per cent zinc, 16.4 grams per tonne silver and 0.34 gram per tonne gold (Assessment Report 9882).

In 1986, a sample (8614-6) of silicified and pyritized mafic volcanic flow assayed 0.26 gram per tonne gold, whereas a sample (8614-40) from trench 4 yielded 2.8 grams per tonne silver, 0.457 per cent lead and 0.725 per cent zinc (Assessment Report 15568).

In 1987, a drillhole on the Twin Mountain zone is reported to have yielded 10.6 grams per tonne gold, 335.3 grams per tonne silver, 3.13 per cent zinc, 2.74 per cent lead and 0.55 per cent copper over 2.37 metres (George Cross Newsletter #237, 1987).

In 1988, a drillhole (T88026) was reported to have been completed to test the subsurface extent of the Twin Mountain zone and yielded 0.24 per cent copper, 1.25 per cent lead, 1.44 per cent zinc and 4.7 grams per tonne silver over an unknown length (Assessment Report 37434). Also at this time, samples from the Twin Mountain zone exposed above the West and East adits yielded 0.01 and 0.10 per cent copper, 10.74 and 16.78 per cent lead, 1.73 and 8.10 per cent zinc and 46.0 and 50.4 grams per tonne silver with 0.38 and 0.16 gram per tonne gold, respectively, whereas two underground samples from the West adit averaged 0.129 gram per tonne gold, 29.2 grams per tonne silver, 0.20 per cent copper, 2.03 per cent lead and 2.43 per cent zinc (Assessment Report 19734).

In 1989, grab samples (TR-89-20-09 and TR-89-19-10) from trenches TR-20 and TR-19, which were designed to test the northwest strike extension of the Twin Mountain zone and are located approximately 600 metres northwest of the West adit, yielded 0.10 and 0.10 per cent lead, 0.61 and 0.35 per cent zinc with 2.4 and 3.4 grams per tonne silver, whereas a 1-metre chip sample (TR-89-20-06) from trench TR-20 assayed 0.09 per cent lead, 0.20 per cent zinc, 1.8 grams per tonne silver and 0.14 gram per tonne gold (Assessment Report 19734).

In 2000, a 1.5-metre chip sample (104718) from an outcrop of phyllites with quartz carbonate veinlets and disseminated pyrite, located on the northwest extension of the Twin Mountain zone, yielded 0.145 gram per tonne gold (Assessment Report 26595).

In 2007, a sample (BRACR002) from the face of the east adit yielded 0.44 per cent zinc and 0.06 per cent lead (Assessment Report 29744).

Work History

Exploration in the area began in the late 1800s. The Twin Mountain occurrence was discovered in 1936 and a program of hand trenching was undertaken.

In 1952 and 1953, the property was optioned by Camoose Mines Ltd. and two exploration tunnels, referred to as the West and East tunnels and totalling approximately 230 metres of underground development, were constructed approximately 400 metres apart to intersect the Twin Mountain vein structure. The West tunnel is reported to have intersected the vein structure and drifting was completed along strike for approximately 63 metres.

In 1966, Sinmax Mines Ltd. optioned the property and conduced a program of soil sampling, geophysical surveys, underground mapping and sampling. In 1969, a program of trenching was completed along the strike of the mineralized vein system.

The Twin claims were staked in 1980 and in 1981, and Apex Energy completed a program of geological mapping, soil sampling and trenching. In 1983 and 1984, Lincoln Resources Incorporated entered into an option agreement with Apex Energy Corp to work on the Twin property. A program of soil sampling and ground magnetic and electromagnetic surveys were completed.

Falconbridge Copper acquired the property from Lincoln Resources in 1984 and conducted mapping, rock sampling, Max-Min II and very low-frequency electromagnetic geophysical surveys. In early 1985, Falconbridge Copper proposed a nine-hole, 2400-metre drill program to test targets on the Rea Gold (MINFILE 082M 191), Austin-Apex and Kamad (MINFILE 082M 277) options. Three drillholes totalling 350 metres were planned for the Austin-Apex property. Only two of the nine diamond drill holes were completed; neither hole intersected the target horizon.

In spring 1985, Falconbridge Copper dropped the option on the property and returned it to Lincoln Resources. Later that year, Lincoln Resources conducted a limited fill-in soil survey. In 1986, Lincoln Resources and Apex Energy hired J.D. Blanchflower to undertake an exploration program on the Twin property. As part of the 1986 program, the 1983 grid was re-established and extended, and further rock and soil sampling and mapping was conducted. Genie electromagnetic surveying and trenching were also completed on the Rea zone.

In late 1986, Esso Minerals Canada optioned the property from Lincoln Resources and Apex Energy. Early in 1987, Esso Minerals conducted a very low-frequency electromagnetic geophysical survey over geochemical target areas. This was followed by 2269 metres of diamond drilling, which resulted in the discovery of a small, gold-rich, massive sulphide-barite lens on the Twin 3 claim. During the summer of 1988, Esso Minerals drilled 1278 metres in eight holes and performed additional geophysics and geological mapping targeting the Rea and Twin Mountain zones.

Homestake Canada Limited acquired Esso's option in 1989 and performed a limited amount of trenching on the Twin Mountain zone. In 1990, Homestake completed 4017 metres of NQ diamond drilling in nine holes and 2235 metres of downhole pulse electromagnetic geophysical surveying in six of the holes. Homestake conducted a further 4069 metres of diamond drilling in six holes in 1991. Four of the Twin drillholes intersected Silver zone mineralization.

In 1999, Eagle Plains Resources staked the Acacia property on the area. The following year, a program of rock, silt and soil sampling was completed. Also during 2000 through 2004, the area immediately west was prospected, sampled, trenched and drilled as the Extra High property (See MINFILE 082M 277). In 2005, Amarc Resources Ltd. completed a program of geological mapping and lithogeochemical sampling on the area as the Sin 1-12 claims of the Max property.

During 2007 through 2012, Eagle Plains Resources Ltd. completed programs of prospecting, geological mapping and geochemical (rock, silt and soil) sampling and 738 line-kilometres of magnetic and radiometric surveys on the area as part of the Acacia property. In 2017, a further program of rock and soil sampling was completed on the property.